NEW 115141
Rendering on http://www.milwaukeepolicenews.com is broken 
https://bugs.webkit.org/show_bug.cgi?id=115141
Summary Rendering on http://www.milwaukeepolicenews.com is broken
Alexandru Chiculita
Reported 2013-04-24 17:41:56 PDT
Open http://www.milwaukeepolicenews.com and start scrolling. Looks like the tile rendering is broken for some of the elements (enable the layer borders to see that).
Attachments
Test case (670 bytes, text/html)
2013-07-10 05:30 PDT, Alexandru Chiculita 		no flags
Details
View All Add attachment proposed patch, testcase, etc.
Alexandru Chiculita
Comment 1 2013-07-10 05:30:22 PDT
Created attachment 206380 [details] Test case Simplified test case that reproduces the issue. The issue is triggered by the fact that now the fixed elements will always force a composited layer. Because of that the parent that sets the clipping also gets a composited layer. Looks like composited fixed elements inside other composited clipping layers was broken in Safari 6 too, but the fixed element was not converted to composited mode. The bug also reproduces in Chromium. Firefox 22 and IE11 do not reproduce the issue and do not clip the fixed element.
Simon Fraser (smfr)
Comment 2 2013-07-10 09:21:13 PDT
Yeah, fixed inside of clipping is broken.
Alexandru Chiculita
Comment 3 2013-07-11 04:30:01 PDT
(In reply to comment #2) > Yeah, fixed inside of clipping is broken. We could detect this case and apply the clipping on the children layers instead of the parent. It wouldn't work for transformed parents, but I think that's ok as that case wouldn't work in 2D mode either. Do you want me to work on that or it's not worth the effort to support that edge-case?
Simon Fraser (smfr)
Comment 4 2013-07-11 13:02:31 PDT
I think this is worth fixing. The tricky part would be an animation on an element between the clipping element and the pos:fixed; we'd have to fall back to software animation in that case so that all the clipping layers can be updated for each frame. But maybe this is the "transformed parents" case you mention. Also, don't forget that transforms act as containing block for fixed position.
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